Quantifying the Magnitude of the Stormtime Subauroral Currents and Electric Fields From 
Data-Theory Comparisons

Liemohn, M.W., Ridley, A.J., Kozyra, J.U., Clauer, C.R., Gallagher, D.L., Ober, D.M.,
C:son Brandt, P., Khazanov, G.V.


The longitudinal asymmetry of the stormtime ring current necessitates field-aligned currents
(FACs) into and out of the subauroral ionosphere. The closure of these FACs through the
ionosphere creates cross-B-field electric fields in this region. These electric fields can 
then alter the flow of plasma through the inner magnetosphere and thus the spatial 
configuration of the ring current. This feedback loop is simulated using a self-consistently 
coupled kinetic transport model for the hot ions and ionospheric potential solver. It is 
shown that the electric fields from the stormtime asymmetric ring current are capable of 
significantly deforming the ring current and plasmasphere, creating noticeable features in 
the global morphology of these plasma populations. Focus is given to the magnetic storm of 
April 11-12, 2001 because of its isolation from other events and the optimal viewing 
orientation of the IMAGE satellite during the event.  The accuracy and validity of the 
simulation results are checked through comparisons with satellite and ground-based 
magnetometer observations. 
		   
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Fall 2002 Meeting of the American Geophysical Union
San Francisco, CA, USA, 6-10 December 2002